Community health advisors (CHAs) play a key role in promoting health in medically underserved communities, including in addressing cancer disparities. There is a need to expand the research on what characteristics make for an effective CHA. We examined the relationship between CHA personal and family history of cancer, and implementation and efficacy outcomes in a cancer control intervention trial. Twenty-eight trained CHAs implemented a series of three cancer educational group workshops for N = 375 workshop participants across 14 churches. Implementation was operationalized as participant attendance at the educational workshops, and efficacy as workshop participants' cancer knowledge scores at the 12-month follow-up, controlling for baseline scores. CHA personal history of cancer was not significantly associated with implementation, nor knowledge outcomes. However, CHAs with family history of cancer had significantly greater participant attendance at the workshops than CHAs without family history of cancer (P = 0.03) and a significant, positive association with male workshop participants' prostate cancer knowledge scores at 12 months (estimated beta coefficient = 0.49, P < 0.01) after adjusting for confounders. Findings suggest that CHAs with family history of cancer may be particularly suitable for cancer peer education, although further research is needed to confirm this and identify other factors conducive to CHA success.